U.S. Pat. No. 4,268,609 discloses a presensitized lithographic printing plate comprising a support having a hydrophilic surface, e.g., an aluminum plate, and a non-silver light-sensitive layer and a negative or direct positive light-sensitive silver halide emulsion layer provided on the support in that sequence, wherein a hydrophilic colloid layer adjacent to the non-silver light-sensitive layer (an embodiment in which the hydrophilic colloid layer is the light-sensitive silver halide emulsion layer is also included) contains a substantially water-insoluble lipophilic resin dispersed therein in finely divided particles.
As preferred examples of the above-described lipophilic resins, resins containing a phenolic hydroxy group, such as a phenol resin, and a mono- or copolymer of hydroxystyrene, are disclosed. With these resins, however, it has been found that although satisfactory results can be obtained when a negative light-sensitive silver halide emulsion layer is used, various problems arise when a direct positive silver halide emulsion layer is used. For example, the sensitivity of the direct positive light-sensitive silver halide emulsion layer is seriously reduced, and minimum density of highlights is increased. As a result, a sharp silver image may not be obtainable. In addition, non-image areas of the lithographic printing plate are stained, printing durability (press life) is degraded and sharpness is reduced.